A novel high-performance photodetector based on two-dimensional perovskite crystals with alternating interlayer cations

Abstract

In this invention, a high-performance photodetector based on 2D bilayered hybrid lead halide perovskite single crystal with ACI phase, with a chemical formula of GAMA2Pb2I7 where GA is C(NH2)3 and MA is CH3NH3,) was fabricated, using a facile and cost-effective method based on cooling crystallization. The single-crystal photodetector exhibits high photoresponsivity, together with correspondingly high detectivity values. Meanwhile, a high-resolution imaging sensor is built based on the GAMA2Pb2I7 single-crystal photodetector, confirming the high stability and photosensitivity of the imaging system.

1 . A method of synthesizing two-dimensional bi-layered lead-halide hybrid perovskite single crystals with ACI (alternating cations in the interlayer) phase, comprising:
 adding a guanidine salt, a methylamine component and a lead salt into a solution of hypophosphorous acid (H 3 PO 2 ) water solution and hydroiodic acid (HI);   heating the mixture to a temperature of 220° C. to 240° C. and stirring to ensure a mixture of starting materials without precipitation; and   cooling the mixture to a temperature of 15° C. to 25° C. to obtain a crystallized product;   wherein the crystallized product is a two-dimensional bi-layered lead-halide hybrid perovskite single crystal having a chemical formula of GAMA 2 Pb 2 I 7 , wherein GA is C(NH 2 ) 3  and MA is CH 3 NH 3  and;   wherein the yield of the two-dimensional bi-layered lead-halide hybrid perovskite single crystal product with ACI phase is at least 70% relative to Pb.   
     
     
         2 . The method of  claim 1 , wherein the guanidine salt is selected from guanidine carbonate, guanidine hydrochloride, guanidinium bromide, guanidinium iodide or guanidine phosphate, or any combinations thereof. 
     
     
         3 . The method of  claim 1 , wherein the methylamine component is selected methylamine, methylamine hydrochloride, methylammonium bromide, or any combinations thereof. 
     
     
         4 . The method of  claim 1 , wherein the lead salt is selected from lead carbonate, lead iodide, lead bromide, lead chloride, lead (II) acetate trihydrate, or any combinations thereof. 
     
     
         5 . The method according to  claim 1 , where the molar ratio of guanidine salt, lead salt and methylamine component is selected from a range of 1:1.5:1.5 to 1:2.5:2.5. 
     
     
         6 . The method according to  claim 1 , wherein speed of cooling the mixture from a range of 65° C. to 85° C. to room temperature of 15° C. to 25° C. is 0.5° C./day to 2° C./day. 
     
     
         7 . A photodetection device comprising the two-dimensional bi-layered lead-halide hybrid perovskite single crystals formed by the method of  claim 1 , disposed on a substrate and having electrodes formed thereon. 
     
     
         8 . The photodetection device of  claim 7 , wherein the electrodes are deposited onto the two-dimensional bi-layered lead-halide hybrid perovskite single crystals by a high-vacuum thermal evaporator at a thickness of 45 nm to 55 nm. 
     
     
         9 . The photodetection device of  claim 7 , wherein the electrodes comprise gold. 
     
     
         10 . The photodetection device of  claim 7 , wherein the substrate is selected from ceramic, glass, polymer, semiconductor, or any combinations thereof. 
     
     
         11 . The photodetection device of  claim 7 , wherein the photoresponsivity of the device is at least 1.50 A/W under an incident light with a wavelength of 400 nm to 700 nm. 
     
     
         12 . The photodetection device of  claim 7 , wherein the detectivity of the device is at least 1.50×10 12  Jones under an incident light with a wavelength of 400 nm to 700 nm.